Dielectric Exhaust Duct

ABSTRACT

The improved dryer flexible exhaust ducting of the present invention is comprised of a flexible exhaust ducting with a nonconductive, high temperature polymer treated coupling member. The dielectric dryer coupling member prevents the travelling of electrical current from an inadvertently energized dryer chassis to the attached flexible ducting and thus prevents the ducting from overheating or melting from the electrical current or igniting flammable materials nearby or contained within the ducting.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No. 15/208,317 filed Jul. 12, 2016 which claims the benefit of and priority to a U.S. Provisional Patent Application No. 62/191,899 filed Jul. 13, 2015, the technical disclosures of which are incorporated by reference. This application claims the benefit of and priority to a U.S. Provisional Patent Application No. 62/371,717 filed Aug. 6, 2017, the technical disclosures of which are incorporated by reference.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to consumer and commercial appliances, and more particularly to consumer and commercial clothes dryers. This invention relates to clothes dryers having an improved output exhaust duct.

2. Description of Related Art

Clothes dryers are a leading cause of residential fires in the United States. In 2010, clothes dryers and washing machines accounted for 4.5% of all reported home structure fires, 1.9% of associated civilian deaths, 2.8% of associated civilian injuries, and 3.1% of associated direct property damage. Clothes dryers accounted for 92% of these fires; washing machines 4%, and washer and dryer combinations accounted for 4%. The risk of fire is roughly equal for gas and electric dryers.

From 2006-2010, the National Fire Protection Association NFPA reported a yearly average of over 15 thousand dryer fires in the United States per year, resulting in a yearly average of 29 deaths, 402 injuries, and approximately $192 million in direct property damage. The leading cause of home clothes dryer and washer fires was failure to clean 32%, followed by unclassified mechanical failure or malfunction 22%. Eight percent were caused by some type of electrical failure or malfunction. Out of these fires, the leading item first ignited in a clothes dryer fire was dust, fiber, or lint, causing 29% of the fires and 85% of the deaths.

Many fires are caused each year by ignition of the flexible exhaust ducting that carries lint and exhaust air from the clothes dryer exhaust outlet to a vent system that is part of the residence. A standard flexible exhaust ducting is comprised of thin, conductive material such as aluminum or a nonconductive material such as vinyl. In flexible exhaust ducting made of nonconductive material, the walls of the ducting typically contain a conductive steel helical spring, in order to retain the tubular shape of the ducting and prevent collapse. The present mode of clothes dryer construction, gas or electric, relies on ridged sheet metal for the output exhaust duct on the dryer. Typically, the exhaust duct (which is part of factory construction and constructed of rigid sheet metal) is conductive. Similarly, the external dryer vent built into residences is typically constructed of conductive metal.

SUMMARY OF THE INVENTION

The present invention is a high temperature polymer coupling member to the flexible exhaust ducting for connecting the flexible exhaust ducting to the dryer exhaust duct and/or the external exhaust vent. This dielectric coupling member prevents any potential electrical current from being conducted through the flexible exhaust ducting. Additionally, this dielectric coupling member can prevent arcing between the flexible exhaust ducting and the dryer chassis, dryer exhaust duct, or the external exhaust duct in the wall. Ridges and external shoulders encircling the coupling member create additional barriers to prevent arcing. For purposes of this patent, a high temperature polymer is defined as one that in the intended usage does not suffer from chemical or mechanical changes that would make it unsuitable for its intended use. The exact temperature characteristics and composition of the polymer may well vary among different designs of clothes dryers.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the apparatus of the present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is an elevation view of the rear of a standard electric or gas dryer;

FIG. 2 is a side view of a standard electric or gas dryer;

FIG. 3 is a side view of an embodiment of the coupling member.

FIG. 4 is a side view of an embodiment of the dielectric flexible exhaust ducting;

FIG. 5 is a side view of a dryer exhaust system with an embodiment of the dielectric flexible exhaust ducting;

FIG. 6 is a cross section view of line 6-6 in FIG. 5 showing the coupling member of the dielectric flexible exhaust ducting connected to the exhaust duct.

FIG. 7 is a cross section view of another embodiment of a coupling member of the dielectric flexible exhaust ducting connected to the exhaust duct.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 depict the back and side views, respectively, of a standard clothes dryer. The rear chassis 10 of the dryer is typically made of conventional sheet metal. The dryer exhaust duct 14 protrudes from the rear chassis 10 of the dryer. The dryer exhaust duct 14 is typically a tubular structure having an outer surface 16 and. an outlet 18. The dryer exhaust duct 14 is typically crafted of the same conventional sheet metal as the rear chassis 10 of the dryer itself.

Referring to FIGS. 3, 4 and 6, the flexible exhaust ducting 30 comprises a coupling member 40 and ducting member 50. The coupling member 40 further comprises a generally tubular first sleeve 41 having an inner surface 42 and outer surface 43 connected to a generally tubular second sleeve 45 having an inner surface 46 and outer surface 47. The inner diameter of the first sleeve 41 is greater than the outer diameter of the dryer exhaust duct 14 and the inner diameter of the second sleeve 45. The second sleeve 45 is positioned within the first sleeve 41 such that a portion of the second sleeve's 45 outer surface 47 is in contact with a portion of the first sleeve's 41 inner surface 42. An internal shoulder 44 is positioned between the first sleeve's 41 inner surface 42 and the second sleeve's 45 inner surface 46. The outer diameter of the first sleeve 41 is greater than the outer diameter of the second sleeve 45 creating an external shoulder 48.

In a preferred embodiment, the first sleeve 41 and second sleeve 45 are integrally constructed as one piece. In another embodiment, the second sleeve 45 may be attached to the first sleeve 41 by adhesive or frictional means. The coupling member 40 is constructed of a high temperature polymer. In another embodiment, the inner surfaces 42, 46 of the coupling member 40 are coated with a high temperature polymer. In both embodiments, the coupling member 40 is dielectric.

Referring to FIGS. 4 and 6, the ducting member 50 is generally tubular in shape having an open first end 51, sidewall 52, and an open second end 53. The inner diameter of the ducting member 50 generally corresponds to the outer diameter of the second sleeve 45 such that the first end 51 of the ducting member 50 may slide over the outside surface 47 of the second sleeve 45. The inner surface 54 of the ducting member 50 may be frictionally engaged with the outside surface 47 of the second sleeve 45. The ducting member 50 abuts the external shoulder 48.

Alternatively, or in addition to, a mechanical device, such as a clamp, may be used to secure a portion of the second sleeve 45 within ducting member 50. The ducting member 50 may be constructed of traditional ducting material such as a thin, conductive material such as aluminum or a nonconductive material such as vinyl, with a steel helical spring to maintain the tubular shape. In another embodiment, the coupling member 40 and the ducting member 50 are integral.

Referring to FIG. 6, the coupling member 40 is fitted to the dryer such that the dryer exhaust duct 14 is positioned within the first sleeve 41 of the coupling member 40. The inner diameter of the first sleeve 41 generally corresponds to the outer diameter of the dryer exhaust duct 14 such that friction secures the coupling member 40 to the dryer exhaust duct 14. The coupling member 40 may be positioned such that it abuts the rear chassis 10 of the dryer but it is not required. The dryer exhaust duct 14 is positioned within the first sleeve 41 such that it abuts the internal shoulder 44. The internal shoulder 44 prevents the dryer exhaust duct 14 from being positioned with the second sleeve 45. The external shoulder 48 prevents the first end 51 of the ducting member 50 from contacting the dryer exhaust vent 14 or the rear chassis 10 of the dryer.

The inner diameter of the dryer exhaust duct 14 generally corresponds to the inner diameter of the second sleeve 45 to prevent any restriction of exhaust flow.

The outer diameter of the dryer exhaust duct 14 generally corresponds to the outer diameter of the second sleeve 45. This permits a traditional ducting member 50 to be positioned around the second sleeve 45 of the coupling member 40.

FIG. 4 depicts an overall dryer exhaust system 60. The dryer exhaust system comprises a dryer exhaust duct 14, flexible exhaust ducting 30, and an external exhaust duct 26 built into the wall 21 of a residence. Dryer lint 24 is also shown in the interior of the ducting member 50. The coupling member 40 is positioned in such a manner that the conductive dryer exhaust duct 14 is not in contact with the conductive ducting member 50. The construction of the coupling member 40 further prevents the potential for arcing. A traditional dryer, with a traditional flexible exhaust duct may be fitted with the coupling member to prevent current flow and arcing. Alternatively, an integral coupling member and ducting member may be utilized.

Another embodiment is disclosed in FIG. 7. The flexible exhaust ducting 130 comprises a coupling member 140 and ducting member 150. The coupling member 140 further comprises a generally tubular first section 141 connected to a generally tubular ridged second section 145. The inner diameter of the first section 141 is greater than the outer diameter of the dryer exhaust duct 14. An external shoulder 148 encircles the first section 141 approximately at the junction where the first section 141 and second section 145 join. Multiple ridges 149 may encircle the second section 145. The ducting member 150 connects to the second section 145. The coupling member 140 is fitted to the dryer such that the dryer exhaust duct 14 is positioned within the coupling member only and preferably within the first section 141. The inner diameter of the first section 141 generally corresponds to the outer diameter of the dryer exhaust duct 14 such that friction secures the coupling member 140 to the dryer exhaust duct 14. The coupling member 140 is constructed of a high temperature polymer. In another embodiment, the inner surfaces of the coupling member 140 are coated with a high temperature polymer. In both embodiments, the coupling member 140 is dielectric.

Although the invention hereof has been described by way of a preferred embodiment, it will be evident that other adaptations and modifications can be employed without departing from the spirit and scope thereof. The terms and expressions employed herein have been used as terms of description and not of limitation; and thus, there is no intent of excluding equivalents, but on the contrary it is intended to cover any and all equivalents that may be employed without departing from the spirit and scope of the invention. 

1. An exhaust system for a clothes dryer comprising a dryer exhaust duct connected to a coupling member constructed of a dielectric material; and a ducting member having a first end connected to said coupling member and a second end connected to an external exhaust duct.
 2. The exhaust system of claim 1 wherein said dielectric material is a high temperature polymer.
 3. The exhaust system of claim 1 wherein said coupling member further comprises a first sleeve having an inner diameter greater than an outer diameter of said dryer exhaust duct; a second sleeve having an inner diameter smaller than said inner diameter of said first sleeve and an outer diameter smaller than the inner diameter of said ducting member.
 4. The exhaust system of claim 3 wherein said dryer exhaust duct and said first sleeve are tubular.
 5. The exhaust system of claim 1 wherein said coupling member further comprises an internal shoulder and an external shoulder wherein said dryer exhaust duct abuts said internal shoulder and said first end of said ducting member abuts said external shoulder.
 6. The exhaust system of claim 3 wherein said first sleeve further comprises an external shoulder.
 7. An exhaust system for a clothes dryer comprising a dryer exhaust duct having a terminal end and a ducting member having a first portion constructed of a dielectric material wherein said first portion is connected to said dryer exhaust duct.
 8. The exhaust system of claim 7 wherein said first portion further comprises an inner surface that is positioned around said dryer exhaust duct such that said terminal end of said dryer duct is within said first portion.
 9. The exhaust system of claim 8 wherein said ducting member comprises a second portion constructed of a dielectric material having ridges positioned along the outside surface of said second portion.
 10. The exhaust system of claim 9 wherein an external shoulder separates said first portion and said second portion.
 11. A coupler for connecting a duct to a dryer exhaust vent comprising a first portion constructed of a dielectric material having an inner diameter greater than an outer diameter of said dryer exhaust duct, an internal shoulder positioned within said first portion having a diameter smaller than said outer diameter of said dryer exhaust duct, and a second portion having an outer diameter smaller than the inner diameter of said duct.
 12. The coupler of claim 11 wherein said second portion is constructed of a dielectric material.
 13. The coupler of claim 11 wherein said first portion further comprises an external shoulder having an outer diameter greater than the outer diameter of said duct.
 14. The coupler of claim 11 wherein said first portion and said second portions are tubular. 